Primary gastrointestinal non-Hodgkin lymphoma accounts for 13-18% of all malignant tumours of small bowel and only 1 % of large bowel tumours (1). Multiple lymphomatous polyposis is a rare entity, characterized by the presence of multiple lymphomatous polyps along the gut (2). Majority of cases with gastrointestinal primary lymphoma are classified histologically as "mantle cell" lymphomas. A 59 year old patient was admitted to our clinic for fatigue and rectal bleeding. Endoscopic examination of the colon revealed an infiltrative-exulcerative lesion of the terminal ileon, a polypoid mass on ileocecal valve and multiple polyps over the entire colon and rectum. Gastroscopy revealed polyps into the duodenal bulb. Histopathological and immunohistochemical studies on biopsy specimens from colon and duodenum confirmed gastrointestinal non-Hodgkin lymphoma, probably "mantle cell" lymphoma. Because she was in an advanced stage she received only cytostatic treatment. A clinical, endoscopical and histopathological follow up at 3, 6 and 12 months was performed.